1. Field of the Invention
The present invention relates to a parts suction apparatus of a module head in a surface mount device, and more particularly, to a parts suction apparatus for suctioning surface mounting parts in a module head of a surface mount device used for mounting surface mounting parts on a printed circuit board.
2. Description of the Related Art
A surface mount device includes a X-Y gantry, a carrier, a module head and a vision system. The carrier is used for carrying the printed circuit board for mounting surface mounting electric and electronic parts (hereinafter, parts) to a working position of the surface mount device. The module head is used for picking up parts and carrying them onto the printed circuit board which is carried to the working position. The module head is mounted in the X-Y gantry and is moved to a X-Y direction to mount parts on the printed circuit board.
The parts carried and mounted onto the printed circuit board are picked up by a nozzle provided at the module head, and a position error of the parts picked up by the nozzle is sensed by the vision system. When an error occurs on the position of the parts picked up by the nozzle, the vision system rotates the nozzle finely to correct the position and then picks up the parts to mount the same on the printed circuit board. The module head picking up parts and carrying them onto the printed circuit board will now be described with reference to the accompanying drawings.
FIG. 1 is a front view of a module head of a surface mount device to which a nozzle rotating apparatus is adapted according to the conventional art. As illustrated therein, the module head 10 includes a plurality of heads 20a each head including a hollow shaft 11, a rotary shaft 12, a guide shaft 13 and a parts suctioning apparatus 20. The hollow shaft 11 is installed inside the rotary shaft 12, and the rotary shaft 12 is installed inside the guide shaft 13. The hollow shaft 11 is installed to be moved in a vertical direction inside the rotary shaft 12, and the rotary shaft 12 is installed to be rotated inside the guide shaft 13.
One end of the rotary shaft 12 is connected with a motor 1a by a timing belt 1b so that it can be rotated finely using a rotatory force generated from the motor 1a. On the outer circumferential surface of the hollow shaft 11, a guide member 11a is formed so that the hollow shaft 11 can be rotated when the rotary shaft 12 is rotated. The guide member 11a is installed inside a guide penetrating groove 12a of the rotary shaft 12. The guide member 11a is installed in such a manner that the hollow shaft 11 can be guided to the guide penetrating groove 12a when moving vertically inside the rotary shaft 12.
An air inlet 13a installed below the guide shaft 13 is used for introducing or running off air to the parts suction apparatus 20. When air is sucked out through the air inlet 13a, the parts suction apparatus 20 sucks parts, and when air is introduced, the parts suction apparatus 20 releases the sucked parts. The construction and operation of the parts, suction apparatus 20 for sucking or removing parts will now be described with reference to the accompanying drawings.
FIG. 2 is a front view of a parts suction apparatus 29 mounted on a hollow shaft 11 shown in FIG. 1, and FIG. 3 is a front sectional view of the parts suction apparatus 29 shown in FIG. 2. As illustrated therein, the parts suction apparatus 20 mainly includes a socket 21, a bolt 22 (refer to FIG. 3), a hatch 23, a holder 24 and a nozzle 25. As illustrated in FIG. 3, when the bolt 22 is connected to the inside of the socket 21, the nozzle 25 is installed inside the holder 24 and then the holder 24 is installed inside the socket 21. Once the holder 24 is installed inside the socket 21, the latch 23 is installed on the socket 21 so that the holder 24 is supported by the socket 21.
To receive elastic force, a first spring 28 is installed on the outer circumferential surface of the socket 21 between the socket 21 and the latch 23, and a second spring 29 is installed between the holder 24 and the nozzle 25. The first and second springs 28 and 29 are used for alleviating impact when sucking parts. A first ball 26 installed below one end of the socket 21 is used for mounting or demounting the holder 24 on the socket 21. A second ball 27 is used for minimizing friction when installing the latch 23 on the socket 21. In order to mount and fix the nozzle 25 to the holder 24 installed on the socket 21 using the first ball 26, a pin hole 25a is formed. The pin hole 25a is installed by fixing the nozzle 25 to the holder 24 by using a pin (not shown). Therefore, a pin (not shown) is penetrated to the pin hole 25a, thereby fixing the nozzle 25 to the holder 24.
In the thusly constructed parts suction apparatus according to the conventional art, there is a problem that since the second spring is used for alleviating impact when sucking parts, the second spring installed between the holder and the nozzle is required to have a predetermined length in order to sufficiently absorb the impact caused by the suctioning of parts, and therefore the length of the nozzle becomes larger.
In addition, in the conventional parts suction apparatus, there is another problem that since a mechanism for elevating the socket to a predetermined height is needed for replacing the nozzle by changing the first ball installed on the socket from the fixed state to the free state, the construction of the parts suction apparatus is complicated and the replacing time of the nozzle is lengthened.
It is, therefore, an object of the present invention to provide a parts suction apparatus of a module head in surface mount device which can reduce nozzle replacement time by simplifying the mount structure of the parts suction apparatus using the plate spring members when mounting the holder to the socket or demounting the same.
It is another object of the present invention to provide a parts suction apparatus which can simplify the structure of the nozzle and decrease the length of the nozzle by using the plate spring members in order to alleviate impact when sucking parts.
To achieve the above object, there is provided a parts suction apparatus of a module head in surface mount device comprising: a socket having a first through hole in an inner longitudinal direction and a fixing member inside the first through hole, one end of the inside of the first through hole being mounted to a hollow shaft by using the fixing member; a nozzle having a second through hole for forming an air passage when sucking parts in an inner longitudinal direction; a coupling member installed to an inside of the first through hole formed the socket and having a third through hole in an inner longitudinal direction and a plurality of plate spring members installed inside the third through hole formed on the socket for supporting the nozzle when being installed at the other end of the inside of the first through hole and for alleviating impact when the nozzle sucks parts; and a holder for fixing the nozzle so that it is not removed from the coupling member when the nozzle is installed inside the third through hole of the coupling member.
Preferably, the nozzle has a taper formed on its outer circumferential surface so that it is supported by the plate spring member installed inside the third through hole of the coupling member, threads are formed on the outer circumferential surface of the coupling member and on the inner circumferential surface of the first through hole, respectively, in order to install the coupling member to the other end of the first through hole formed to the socket and a plurality of slots are formed to the inner circumferential surface of the third through hole of the coupling member in order to install the plate spring member inside the third through hole of the coupling member and are installed in opposition to each other.
Preferably, the number of the slots installed in opposition to each other is two and the number of the plate spring members installed at the slots formed inside the third through hole of the coupling member is identical to that of the slots, i.e., a first plate spring and a second plate spring, the plate spring member is provided with a shim in order to control elastic force or to control the initial position of the nozzle, and the holder has a plurality of latching members formed at predetermined portions so that the nozzle installed at the coupling member cannot be removed and the latching members are inserted into the slots formed to the inner circumferential surface of the third through hole of the coupling member.